J. Bart Classen
John Barthelow Classen is an American immunologist and anti-vaccinationist. He received his M.D. from the University of Maryland, Baltimore in 1988, his M.B.A. from Columbia University in 1992 and obtained his medical license in October 1997. He is best known for publishing research concluding that vaccines, in particular the Hib vaccine, cause insulin-dependent diabetes mellitus, a hypothesis he proposed based on experiments he conducted on mice in 1996. His views are disputed and considered unverified.